Statistics of stellar variability from Kepler : I. Revisiting Quarter 1 with an astrophysically robust systematics correction
We investigate the variability properties of main sequence stars in the first month of Kepler data, using a new astrophysically robust systematics correction, and find that 60% of stars are more variable then the active Sun. We define low and high variability samples, with a cut corresponding to twi...
| Main Authors: | , , |
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| Format: | Journal article |
| Language: | English |
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EDP Sciences
2012
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| _version_ | 1797105818267549696 |
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| author | McQuillan, A Aigrain, S Roberts, S |
| author_facet | McQuillan, A Aigrain, S Roberts, S |
| author_sort | McQuillan, A |
| collection | OXFORD |
| description | We investigate the variability properties of main sequence stars in the first month of Kepler data, using a new astrophysically robust systematics correction, and find that 60% of stars are more variable then the active Sun. We define low and high variability samples, with a cut corresponding to twice the variability level of the active Sun, and compare the properties of the stars belonging to each sample. We show tentative evidence that the more active stars have lower proper motions and may be located closer to the galactic plane. We also investigate the frequency content of the variability, finding clear evidence for periodic or quasi-periodic behaviour in 16% of stars, and showing that there exist significant differences in the nature of variability between spectral types. Of the periodic objects, most A and F stars have short periods (< 2 days) and highly sinusoidal variability, suggestive of pulsations, whilst G, K and M stars tend to have longer periods (> 5 days, with a trend towards longer periods at later spectral types) and show a mixture of periodic and stochastic variability, indicative of activity. Finally, we use auto-regressive models to characterise the stochastic component of the variability, and show that its typical amplitude and time-scale both increase towards later spectral types, which we interpret as a corresponding increase in the characteristic size and life-time of active regions. |
| first_indexed | 2024-03-07T06:52:49Z |
| format | Journal article |
| id | oxford-uuid:fd1b9a1d-8e91-4546-89ec-a68aca280fc2 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T06:52:49Z |
| publishDate | 2012 |
| publisher | EDP Sciences |
| record_format | dspace |
| spelling | oxford-uuid:fd1b9a1d-8e91-4546-89ec-a68aca280fc22022-03-27T13:26:21ZStatistics of stellar variability from Kepler : I. Revisiting Quarter 1 with an astrophysically robust systematics correctionJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:fd1b9a1d-8e91-4546-89ec-a68aca280fc2EnglishSymplectic Elements at OxfordEDP Sciences2012McQuillan, AAigrain, SRoberts, SWe investigate the variability properties of main sequence stars in the first month of Kepler data, using a new astrophysically robust systematics correction, and find that 60% of stars are more variable then the active Sun. We define low and high variability samples, with a cut corresponding to twice the variability level of the active Sun, and compare the properties of the stars belonging to each sample. We show tentative evidence that the more active stars have lower proper motions and may be located closer to the galactic plane. We also investigate the frequency content of the variability, finding clear evidence for periodic or quasi-periodic behaviour in 16% of stars, and showing that there exist significant differences in the nature of variability between spectral types. Of the periodic objects, most A and F stars have short periods (< 2 days) and highly sinusoidal variability, suggestive of pulsations, whilst G, K and M stars tend to have longer periods (> 5 days, with a trend towards longer periods at later spectral types) and show a mixture of periodic and stochastic variability, indicative of activity. Finally, we use auto-regressive models to characterise the stochastic component of the variability, and show that its typical amplitude and time-scale both increase towards later spectral types, which we interpret as a corresponding increase in the characteristic size and life-time of active regions. |
| spellingShingle | McQuillan, A Aigrain, S Roberts, S Statistics of stellar variability from Kepler : I. Revisiting Quarter 1 with an astrophysically robust systematics correction |
| title | Statistics of stellar variability from Kepler : I. Revisiting Quarter 1 with an astrophysically robust systematics correction |
| title_full | Statistics of stellar variability from Kepler : I. Revisiting Quarter 1 with an astrophysically robust systematics correction |
| title_fullStr | Statistics of stellar variability from Kepler : I. Revisiting Quarter 1 with an astrophysically robust systematics correction |
| title_full_unstemmed | Statistics of stellar variability from Kepler : I. Revisiting Quarter 1 with an astrophysically robust systematics correction |
| title_short | Statistics of stellar variability from Kepler : I. Revisiting Quarter 1 with an astrophysically robust systematics correction |
| title_sort | statistics of stellar variability from kepler i revisiting quarter 1 with an astrophysically robust systematics correction |
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